1、February 2017 English price group 10No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 11.040.70!%anw“2627584www.din.d
2、eDIN EN ISO 10938Ophthalmic optics Chart displays for visual acuity measurement Printed, projected and electronic (ISO 10938:2016);English version EN ISO 10938:2016,English translation of DIN EN ISO 10938:2017-02Augenoptik Anzeigetafeln fr die Sehprfung Gedruckt, projiziert und elektronisch (ISO 109
3、38:2016);Englische Fassung EN ISO 10938:2016,Englische bersetzung von DIN EN ISO 10938:2017-02Optique ophtalmique Dispositifs daffichage de tableaux doptotypes destins au mesurage de lacuit visuelle Tableaux doptotypes imprims, projets et affichs par des moyens lectroniques (ISO 10938:2016);Version
4、anglaise EN ISO 10938:2016,Traduction anglaise de DIN EN ISO 10938:2017-02SupersedesDIN EN ISO 10938:199807www.beuth.deDocument comprises 15 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.02.17 DIN EN ISO 10938:2017-02 2 A com
5、ma is used as the decimal marker. National foreword This document (EN ISO 10938:2016) has been prepared by Technical Committee ISO/TC 172 “Optics and photonics”, Subcommittee SC 7 “Ophthalmic optics and instruments” in collaboration with Technical Committee CEN/TC 170 “Ophthalmic optics” (both secre
6、tariats are held by DIN, Germany) with the active participation of German experts. The responsible German body involved in its preparation was DIN-Normenausschuss Feinmechanik und Optik (DIN Standards Committee Optics and Precision Mechanics), Working Committee NA 027-01-08 AA Augenoptik. The DIN St
7、andards corresponding to the International Standards referred to in this document are as follows: ISO 8596 DIN EN ISO 8596 ISO 15004-1 DIN EN ISO 15004-1 Amendments This standard differs from DIN EN ISO 10938:1998-07 as follows: a) the Scope has been extended to include electronic systems for the di
8、splay of optotypes; b) normative references have been updated; c) new terms have been included; d) requirements for optotypes have been revised; e) requirements for printed charts, projected displays and electronic screens have been specified. Previous editions DIN EN ISO 10938: 1998-07 DIN EN ISO 1
9、0938:2017-02 3 National Annex NA (informative) Bibliography DIN EN ISO 8596, Ophthalmic optics Visual acuity testing Standard optotype and its presentation DIN EN ISO 150041, Ophthalmic instruments Fundamental requirements and test methods Part 1: General requirements applicable to all ophthalmic in
10、struments DIN EN ISO 10938:2017-02 4 This page is intentionally blank EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 10938 October 2016 ICS 11.040.70 Supersedes EN ISO 10938:1998English Version Ophthalmic optics - Chart displays for visual acuity measurement - Printed, projected and electr
11、onic(ISO 10938:2016) Optique ophtalmique - Dispositifs daffichage de tableaux doptotypes destins au mesurage de lacuit visuelle - Tableaux doptotypes imprims, projets et affichs par des moyens lectroniques(ISO 10938:2016) Augenoptik - Anzeigetafeln fr die Sehprfung - Gedruckt, projiziert und elektro
12、nisch(ISO 10938:2016) This European Standard was approved by CEN on 12 September 2016. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists
13、 and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under t
14、he responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugo
15、slav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN
16、 DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 10938:2016 EEuropean foreword .3Introduction 51 Scope . 62 N
17、ormative references 63 Terms and definitions . 64 Requirements 74.1 Optotypes . 74.1.1 Size of optotypes 74.1.2 Luminance of background . 74.1.3 Contrast of optotypes 84.1.4 Quality of presentation . 84.1.5 Resolution 84.2 Requirements specific to optically projected displays . 84.2.1 Focus range .
18、84.2.2 Projector screens . 84.3 Requirements specific to printed charts . 84.4 Range of compliance 84.5 Conformity to ISO 15004-1 95 Test methods . 95.1 Type tests . 95.2 Conformity 95.3 Resolution . 96 Accompanying documents 97 Marking, labelling and packaging . 10Bibliography . 11Contents PageDIN
19、EN ISO 10938:2017-02 EN ISO 10938:2016 (E) 2Foreword .4European foreword This document (EN ISO 10938:2016) has been prepared by Technical Committee ISO/TC 172 “Optics and photonics” in collaboration with Technical Committee CEN/TC 170 “Ophthalmic optics” the secretariat of which is held by DIN. This
20、 European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2017, and conflicting national standards shall be withdrawn at the latest by April 2017. Attention is drawn to the possibility that some of the el
21、ements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 10938:1998. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the foll
22、owing countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
23、Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 10938:2016 has been approved by CEN as EN ISO 10938:2016 without any modification. DIN EN ISO 10938:2017-02 EN ISO 10938:2016 (E) 3 ForewordISO (the In
24、ternational Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee h
25、as been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical
26、 standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in ac
27、cordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Deta
28、ils of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an en
29、dorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.ht
30、ml.The committee responsible for this document is ISO/TC 172, Optics and photonics, Subcommittee SC 7, Ophthalmic optics and instruments.This second edition cancels and replaces the first edition (ISO 10938:1998), which has been technically revised.DIN EN ISO 10938:2017-02 EN ISO 10938:2016 (E) 4 In
31、troductionThe purpose of this International Standard is to provide for standardization of certain characteristics of displays of optotypes used for measurement of visual acuity in general clinical practice. These characteristics include size specification, luminance, contrast, and resolution of the
32、optotypes. It applies to displays intended for measurement of visual acuity over a limited, but clinically useful, range of acuities.The principles of standardized visual acuity measurement, including the arrangement of optotypes on the display, are presented in standards adopted by the National Aca
33、demy of Sciences in the United States of America and the Consilium Ophthalmologicum Universal as referenced in the Bibliography. This International Standard is not intended to address these principles, but they are included in an annex in ISO 8596.Due to practical design considerations and physical
34、limitations of most general-purpose clinical visual acuity measurement systems, the chart design features specified in the reference standards can usually be met for only a limited range of acuity presentations. Other chart display designs are often required for special clinic visual acuity measurem
35、ents, such as for low-vision patients or for research purposes.DIN EN ISO 10938:2017-02 EN ISO 10938:2016 (E) 5 1 ScopeThis International Standard applies to displays of optotypes generated by chart projectors and all other visual acuity measurement systems that use recognition of high-contrast opto
36、types and that are designed for general use, including optotypes printed on media (either opaque or intended for transillumination), those generated electronically, and those produced by optical projection.2 Normative referencesThe following documents, in whole or in part, are normatively referenced
37、 in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 8596, Ophthalmic optics Visual acuity testing Standard optotype and its pres
38、entationISO 15004-1, Ophthalmic instruments Fundamental requirements and test methods Part 1: General requirements applicable to all ophthalmic instruments3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1optotypesymbol used in the measurement of
39、visual acuity3.2standard optotypeLandolt ring for which the gap can be oriented in eight different positionsNote 1 to entry: The Landolt ring is specified in ISO 8596.3.3Snellen fractionnotation for specifying the angular subtense of an optotype (3.1), expressed as a fraction with the numerator bein
40、g the distance at which visual acuity is tested, commonly in metres or feet, and the denominator being the distance at which the critical detail (3.9) (limbs of the optotype) within the optotype subtends 1 of arcEXAMPLE A 6/6 letter has limbs that subtend 1 of arc at 6 m.Note 1 to entry: For project
41、ed charts and electronic acuity displays, it is common to calibrate the size of the optotype to subtend the desired minutes of arc at test distances other than 6 m. For example, for a short 4 m room, the letter equivalent in angular subtense to the 6/6 letter is 2/3 the size of a true 6/6 letter. Ho
42、wever, such a reduced letter is still labelled as 6/6. In this convention, the label 6/6 implies the limbs of the letter subtend 1 of arc at the reduced test distance.DIN EN ISO 10938:2017-02 EN ISO 10938:2016 (E) 6 3.4decimal acuityreciprocal of the minimum angle of resolution (3.5) in minutes of a
43、rcNote 1 to entry: This method of noting the angular subtense of a limb of an optotype (3.1) is also found by writing the Snellen fraction (3.3) as a decimal. For example, Snellen visual acuities 6/6 and 6/12 are decimal acuities 1,0 and 0,5, respectively.3.5resolutionsmallest separation between two
44、 lines for which the lines can be distinguished as two separate lines3.6focus rangemaximum and minimum distances from a projector at which a focused image of the visual acuity chart can be displayed3.7linegroup of optotypes (3.1) having the same size arranged in a straight row across the display3.8p
45、ixelsmallest element, or point sample, that can be individually processed on an electronic display3.9critical detailsmallest feature in an optotype (3.1) that is considered necessary to distinguish the optotype from the other optotypes4 Requirements4.1 Optotypes4.1.1 Size of optotypesEach size of a
46、set of optotypes shall be specified in terms of the size of critical detail common to that set of optotypes. For example, for the Landolt ring, the critical detail is the gap. The permissible deviation is 5 %.NOTE 1 If letters or figures are used for visual acuity measurement, then it should be ackn
47、owledged that these normally show large differences in legibility, even if the size and width of stroke are identical. The impact of this variability can be reduced by choosing letters or figures that are comparable to one another. Comparability can be established for each letter or figure by showin
48、g that its effective resolution is equivalent to that of the standard optotype in a direct comparative test.NOTE 2 See ISO/TR 19498 for description of a method for the correlation of optotypes.4.1.2 Luminance of backgroundThe luminance of the background surrounding the optotype, as viewed by the patient, shall be between 80 cd/m2and 320 cd/m2and shall be specified by the manufacturer.NOTE 1 The recommended luminance is 200 cd/m2.The
